smoris
Junior Member
Posts: 31
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Post by smoris on Apr 30, 2008 2:17:36 GMT -5
Hi all, i have a '93 SR 500 with a 428 chain, 20T front and 55T on the rear.
I want a higher top speed cause i feel the engine can pull a 'smaller' gear ratio, i would like a smaller sprocket on the rear, but i can't find one for a 428 chain...
what should i do?
Are there other sprockets (from other type chains) that fit these chains? or do i have the change the chain to?
Thanks
I
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mikec
Junior Member
Posts: 60
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Post by mikec on Apr 30, 2008 3:08:35 GMT -5
Hi smoris,
You could just change it back to standard,
You will have to buy a new chain eventually anyway.
Which is a 530 chain, 104 links, front sprocket is 16 teeth and rear sprocket is 42 teeth.
I run a standard chain and rear sprocket but have a 17 teeth on the front this drops the
revs a little at any given speed.
With this setup my SR cruises without much vibration at 90-95Kph. and about 3750rpm
But I pretty sure my tacho is out, I got some oil in the back of it some time ago and it
went doolally for a while.
Hope this helps, Cheers, MikeC.
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Post by aero on Apr 30, 2008 4:49:26 GMT -5
That's a wierd set up!
The parts book says that a 16 front and 55 rear with 428 chain is standard for a 1995 model.
The simple way round your problem is to use XT500 sprockets as these give you a wide choice of sizes. You will need a 520 chain though.
The standard gearing on the old SR500 is 16 (with options of 17 and 15) while the rear is 42 with a 530 chain.
As they are using such a large rear sproket on later machine did they de-tune them? Also a 428 chain is EXTREMELY light for a 500cc single, which would seem to point to a lower power output as well.
I run a 17-42 with 530 chain on my every day SR500 and that seems to cruise nicely at 70 mph. I'm building a special that will probably run a 17-38 with 520 chain.
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Post by StewRoss on Apr 30, 2008 4:56:39 GMT -5
Yes you should be able to go to a 520 or 530 chain...check the splines though...17/41/42 would be fine with that chain sizing. Standard SR gearing here was 16/44...with a 530 chain. SR  |
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Post by caferacercarl on May 1, 2008 0:09:25 GMT -5
go the 520 chain, use the XT,TT front spacer, gearing like stew say's, he knows, rear sprocket you can go down to 41 without trimming the rear sprocket boss, I think the modern cross referance is WR400F rear, you can get a 40 but thats the limit with a yammy rear hub. Carl.
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Post by StewRoss on May 1, 2008 2:01:21 GMT -5
Interesting about the WR400F rear sprocket Carl... SR |
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smoris
Junior Member
Posts: 31
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Post by smoris on May 1, 2008 3:53:15 GMT -5
yes i could use a 520 or 530 chain, but the problem is i can't fit an other front sprocket on the secondary gear axle, it has 25mm diameter and most sprockets don't fit this diameter. so i think i will get a 520 chain, 50T rear sprocket and leave the 20T on the front, that will do the trick i guess. And my bike doesn't have reduced power output ;D officially it has 19kW but it is opened up to 24/25kW thx for the fast replies guys I am planning to fit a wiseco 90mm and a mikuni 36mm during next winter (december for me) with that setup i will need new gearing i guess  |
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Post by aero on May 1, 2008 5:01:12 GMT -5
you'll want the 520 chain then!
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Post by shibuyagas78 on May 1, 2008 7:35:43 GMT -5
The combo of 428 - 20 - 55 or 428- 19 - 55 is a very common combo on the majority late model SR's and will be found on every second late model bike. The 428 20 and the 55 are standard Yamaha issue and the p/n if ever needed is: for the 20 tooth: 3FH-17460-10 and for the 55: 3GW-25455-20. AFAM list 428 sprockets for both the SR400 and SR500 late model bikes in a range of sizes as follows: 51,52,53,54,55,56,57,58,59. ISA industries list 51 through to 57 and Sunstar do 55,56. They are listed but wether or not they are available is another thing? Most of these after market sprockets can get expensive and cost about the same for a rear sprocket only as a front and rear 520 pair (due to material, make etc etc etc). So if your chain and sprockets are at the end of their life just do the 520 convert and save having the problems that will occur with an un-compatible "old chain" and new rear sprocket ( its a waste to kill an expensive after market sprocket with an old chain ). But If you have a new 428 chain and good 20 tooth up front then maybe consider just playing with the rear if your agent for AFAM can help. In the end the 520 convert is a good option and parts will be more common in future when needing them again ( well that is if you cant get the 428 after market sprocket range where you live ).
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Post by chew652 on May 1, 2008 17:20:57 GMT -5
yes i could use a 520 or 530 chain, but the problem is i can't fit an other front sprocket on the secondary gear axle, it has 25mm diameter and most sprockets don't fit this diameter. so i think i will get a 520 chain, 50T rear sprocket and leave the 20T on the front, that will do the trick i guess. And my bike doesn't have reduced power output ;D officially it has 19kW but it is opened up to 24/25kW thx for the fast replies guys I am planning to fit a wiseco 90mm and a mikuni 36mm during next winter (december for me) with that setup i will need new gearing i guess If I read this correctly you want to leave your 428 20 tooth front sprocket installed. You can not install a 520 chain and still use this sprocket. I believe 428 chain has a 1/2 inch pitch and the 520/530 chains are 5/8 inch pitch. Sorry ,just won't go. If I have read this wrong I appologize. |
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smoris
Junior Member
Posts: 31
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Post by smoris on May 2, 2008 2:32:12 GMT -5
Ok i think i start to understand, all i have to do is buy 520 chain and 520 sprockets, both front and rear.
the problem is, i think that 520 front sprockets wont fit the axle...
correct me if i'm wrong.
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Post by aero on May 2, 2008 3:26:11 GMT -5
Certainly the older bikes you can use 520 as a direct replacement. I have one SR that i fitted 520 chain and sprockets straight on, no mods or spacers or bugger all.
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Post by chew652 on May 2, 2008 7:16:51 GMT -5
Ok i think i start to understand, all i have to do is buy 520 chain and 520 sprockets, both front and rear. the problem is, i think that 520 front sprockets wont fit the axle... correct me if i'm wrong. I don't think Yamaha would have changed the transmission countershaft to fit a different pitch sprocket.It would be simpler to just make a sprocket to fit. I think any countershaft sprocket(front) made for theSR/XT/TT 500 should fit. You can buy complete 520 kits from some places. Example :http://www.thumperstuff.com/SRXTTT.html I think these guys will make you any sprocket you want if you call them. www.sprocketspecialists.com/ |
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smoris
Junior Member
Posts: 31
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Post by smoris on May 2, 2008 8:47:19 GMT -5
ok thx all, i'm going for the 520 convertion, that's going to be the easiest way to get higher gearing.
someone knows a goot sprocket combo for a 90mm wiseco, 36mm mikuni flatslide and k&n filter. I have open exaust.
thx guys
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Post by StewRoss on May 2, 2008 17:02:54 GMT -5
Hi for your gearing try 17/41 or 40...the only thing you need to make sure of is that the old countershaft has the same size and spline as the newer bikes... Count up the splines and see if you can measure the outside diameter of the shaft...they are probably the same, but you never know until you try. Here's a pic of an early style sprocket for my DCM to change gearing for racing...a 15 tooth 520 one to suit an XT/TT500.  SR |
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